Synopsis On 18 December 2000 in darkness, while under tow of the tug MillerRichmond, the second of two loaded barges, the Miller201, struck the Pitt River Highway Bridge which spans the Pitt River between Douglas Island and Chatham Reach in British Columbia. The couplers between the two barges broke after the barge struck the protection pier causing the Miller201 to break free from the tow. The striking caused extensive damage to the protection pier. There was no major disruption to either highway bridge traffic, or to marine traffic. No one was injured and there was no pollution as a result of this occurrence. Ce rapport est galement disponible en franais. 1.0 Factual Information 1.1 Particulars of the Vessels 1.1.1 Description of the Vessels The MillerRichmond (SeePhoto1) is a shallow draft steel tug with the superstructure located forward. The vessel is equipped with a hydraulically operated towing winch on the after deck with 670metres (m) of 28millimetre (mm) diameter steel wire towing cable, and a 25mm diameter steel wire towing bridle approximately 17m in length. Two 100mm diameter polypropylene couplers, each approximately 10m in length and fitted with eyes at both ends, are used to connect barges. The tug is powered by two diesel engines driving twin fixed-pitch propellers, with twin rudders for each propeller. The wheel-house is well laid out, with propulsion controls arranged on the main console amidships. A second control console is located at the after end of the boat deck abaft the funnels. Both control stations are fitted with pneumatic abort systems to allow the cable to run freely off the towing winch drum in the event of an emergency. Barges Miller201 Miller206 Both barges of steel construction, are flat decked, non-self-propelled and unmanned. The Miller201 (SeePhoto2) is fitted with a hydraulically-operated stern ramp. In the stowed position, the ramp has a vertical height of 12m, and requires the Pitt River Highway Bridge to be swung open to enable transit. Photo2. The barge Miller201 with ramp 1.2 Description of Pitt River Bridges There are three bridges spanning the Pitt River at Chatham Reach, British Columbia. The Pitt River Railroad Bridge is operated and controlled by the Canadian Pacific Railway Company (CP). Approximately 305m to the north is the Pitt River Highway Bridge which is operated by the provincial Ministry of Transportation.2 The highway bridge consists of two bridge spans 76m apart. They form a part of the Lougheed Highway connecting the City of Port Coquitlam to the Municipality of Pitt Meadows, British Columbia (SeeAppendixA). The Highway Bridge spans are fitted atop elliptically shaped concrete piers which have protection piers extending approximately 53m both up and down stream. The protection piers are constructed of wood pilings, with cross and diagonal timber bracing bolted to the pilings. Each protection pier has a protective abutment, constructed of wooden pilings and fir timber sheathing. The approximate vertical clearance under the highway bridges is 8.5metres. A downbound vessel encounters the north section of the road bridge first, followed by the south section and then the railroad bridge. 1.3 History of the Voyage On 15 December 2000, the master of the tug MillerRichmond contacted the Pitt River Highway and Rail Bridges and arranged to transit the bridges upbound on 18December2000 at 0430 Pacific standard time3. At 1730, 17 December 2000, the MillerRichmond departed Delta, British Columbia towing the two empty barges Miller206 and Miller201 to load rocks at the Columbia Bithulic Quarry, some 21miles away and four miles north of the Pitt River Bridges (SeeAppendixB). The tug and tow arrived at the Pitt River Rail Bridge at 0330, 18December2000, and awaited the arrival of the assist tug NellieIrene. The master confirmed his transit time of 0430 to the bridge tenders. On schedule, the tug and tow passed through the rail bridge at 0430. Soon after, and when the tug and tow were about mid-way between the rail and road bridges, the tug's master was informed that the bridge tender was unable to open the south road bridge. The tow was stopped and Miller206 was coupled to the NellieIrene. Since this barge did not have a ramp to hamper its passage under the bridge, it was towed to the stone quarry. The MillerRichmond and the barge Miller201 were secured in the area between the rail and road bridges until repairs to the bridge were effected at 0900. The south bridge opened to marine traffic at 0915, after which the tug and its tow were able to continue on passage to the stone quarry. Loading was completed at 1700 that same day and the master contacted the highway bridge tender to make arrangements to transit the bridges downbound at 1900. He made contact by cellular telephone as he was unable to contact the bridge tender on very high frequency radio (VHF) channel74, the designated working frequency. The bridge tender was on the lower level of the control tower (where there is no VHF) when the VHF call was made. The MillerRichmond, with the loaded barges in tow, departed the berth at 1730 on 18December2000 bound for the Fraser River. To transit the bridge spans, the Miller206 was made fast to the tug on a short tow followed in tandem by the Miller201. At Harken 3 Grounds, approximately one mile upstream of the north bridge, the transit time of 1900 was confirmed with the tenders of both the rail and the road bridges. The tug NellieIrene was standing by upstream of the north bridge to assist as required. In the MillerRichmond's wheel-house were the master and the two crew members. Speeds were varied in order to arrive at the desired time. At 1840, the bridge tender informed the master of the tug by VHF radio that the south span of the bridge would not open. The tug was 3/8of a mile (700m) upstream of the north bridge and proceeding at an estimated 5.5knots over the ground. The master chose to abort the transit while he still had the opportunity to do so. Speed was reduced and a turn to port commenced although the master knew that the width of the river did not offer him enough room to execute a 180turn and that he would almost certainly run aground. Approximately three minutes later, and half way into the turn, he was informed by the bridge tender that the span was now opening. The master then decided to abort the turn to port and attempted to realign the tug and tow for the transit. However, he found it difficult as the tow was now over towards the south (port) side of the river while the bridge span was to starboard. The assisting tug NellieIrene was standing by his port side. As the MillerRichmond proceeded slowly into the draw, the tug and the first barge passed clear. However, the starboard forward corner of the Miller201 came into contact with the cement protection pier, resulting in the couplers between the barges breaking and the Miller201 being separated from the rest of the tow. The MillerRichmond with the Miller206 in tow continued on, passing through both the road bridges, while the Nellie Irene pushed the Miller201, which was still on the upstream side of the north bridge, away from the contact point. The Miller206 was secured to a log boom below the rail bridge and the MillerRichmond returned to tow the Miller201 through the two road bridges assisted by the NellieIrene. The MillerRichmond's master then made arrangements for a damage inspection of the bridge. Later both barges were re-coupled and taken down to Miller's Delta yard where they were secured at 0500, 19December2000, in readiness for discharging. 1.4 Damage 1.4.1 Damage to Bridge The bridge pier protection was damaged extensively. The concrete front of the bridge pier was damaged, and the stringers on top of the pier protection were broken/cracked. Some stringer anchoring bolts required replacing. The sheathing planks of the protection piers are damaged frequently. This damage is rarely reported. 1.4.2 Damage to Vessels The Miller201 suffered extensive damage to the shell on the starboard forward corner in way of the collision bulkhead. 1.5 Certification The MillerRichmond had a Steamship Inspection Certificate valid until 14October2001. The barges Miller201 and Miller206, being non-propelled barges and not carrying pollutants, were not required to undergo inspection by the Marine Safety Branch of Transport Canada. 1.5.1 Personnel The master of the MillerRichmond holds a Master Home Trade 350Ton Certificate of Competency issued by Transport Canada in1975 and re-issued with a STCW954 endorsement in1997. He has 33years of experience on the Fraser and Pitt Rivers, and has sailed as master of the MillerRichmond since1988. The deckhands held no certificates, nor were they required to. The road bridge tender on duty at the time of the occurrence underwent a seven-day training program in the operation of the Highway Bridge after new software was installed in December 1997. This training was conducted by a representative of the software developers. 1.6 Weather, Tide and Current Information Weather conditions were fine and clear, with no wind and calm seas in the sheltered waters of Pitt River. Tide and current information for the area is referenced on Point Atkinson, English Bay, British Columbia. At the time of the occurrence the combined effect of the ebb tide and the current was 3.3knots. 1.7 Highway and Marine Traffic Density Some 80000vehicles pass over the Pitt River Bridge every week day, approximately 40000on Saturdays and somewhat fewer on Sundays. Ambulances use the bridge during medical emergencies at least once a day. A delay caused by an extended road closure results in a major build up of highway traffic on both sides of the bridge. The majority of marine traffic traversing the Pitt River Bridges does not require the bridge spans to be opened as most tugs, tows and pleasure craft do not have height restrictions. The Pitt River Bridges are opened about once a week for commercial traffic bound for the quarry and other destinations upstream. During the summer season, the bridges are also opened for large pleasure craft. 1.8 Bridge Control Tower The Control Tower is a two-level structure located between the north and south road bridges, the upper level of which offers an all-round 360view. It is manned round the clock by a bridge tender. The upper level of the tower houses 17monitors that are connected to cameras scanning different sections of the highway. The cameras can be controlled from the tower to swing through 360 and also zoom in for close-ups. This enables the bridge tender to locate any traffic buildups and divert emergency vehicles as and when needed. In addition, they allow the bridge tender to safely implement and remove highway counter-flow operations as required. Two Video Display Units (VDU), located in the control station on the upper level, serve to both monitor and control the opening and closing of the bridge spans. One of these is the 'Fault Monitoring Screen', while the other 'Control Screen' covers the entire 'swing' operation. It offers a continuous graphic representation of the position of the bridge span during an opening or closing operation. The 'Fault Monitoring' VDU does not provide audio indication of a fault and, in order to catch errors as soon as they occur, it is essential that the bridge tender monitor the two screens during the opening/closing process. The lower level of the tower houses two sets of two Programmable Logic Control units (PLCs), one of which serves as an emergency backup to the main unit. These PLCs interface with the VDU screens on the floor above and via an analog/digital interface, control the sequence of operation of the electric motors, 'wedges', 'end lifts', 'centering pin' etc. in order to make the bridge span 'open' or 'close'. The PLCs also manage the 'Lane Control' process, which takes care of the road traffic gates, the counter-flow systems, the audio and visual advance warnings for road and visual warnings for marine traffic. Washrooms for the bridge tenders are also located at this level. The public can access the control tower by easily bypassing security arrangements. Bridge tenders have been threatened by irate motorists who have accessed the tower when delays, caused by malfunctions, occur. 1.9 Communications 1.9.1 Fraser River The Pitt River Bridges are located outside the Fraser River Vessel Traffic reporting zone of Vancouver Marine Communications and Traffic Services (MCTS). 1.9.2 Control Tower The upper level of the control tower is equipped with a VHF radiotelephone and a land line telephone. The lower section is equipped only with a land line telephone. 1.9.3 MillerRichmond The tug is equipped with both VHF and cellular telephones. 1.10 Operation of Bridge Spans Prior to 1998, a bridge tender operated electrical switches to control the north and south swing spans. The switches controlled the direction of movement of various crown and pinion gears, which caused the swing portion of the bridge span to open or close. The two spans differ from each other in the machinery that is used to accomplish the 'turning'. The north span, which is the newer of the two, has electro-hydraulic components, while the south span has electro-mechanical components. The control of the open/close operation of the Pitt River highway bridge spans, traffic signals and gates was computerized in1998. It was part of a plan to control all the bridges in the Fraser River electronically, from one central command station. The Pitt River bridge is the first to be so converted and a number of independent contractors were hired by the provincial Ministry of Transportation to carry out the project. To 'open' or 'close' a swing span, the bridge tender has to initiate the operation on the 'control' VDU, using his 'mouse'. The PLCs then automatically execute the operation, while a continuous status display of the process is provided on the VDUs. The bridge tender monitors the process and in the event of a malfunction, can immediately switch over to a 'manual' mode of control. In this mode the programme in the PLCs is bypassed, and the bridge tender follows appropriate prompts on his VDU screen, to 'open' or 'close' the span. Electricity for the operation of the bridges is supplied from both Port Coquitlam and Pitt Meadows. To ensure a continuous supply of power in the event of a breakdown of either source, a 'Transfer Switch' automatically changes over to the other one. The basic components directly related to the bridge openings are the 'end lifts', the 'wedges' and the 'centering pin'. In the case of the south span, which is electro-mechanical, signals are sent to an electric motor which starts the process of the 'end lifts' raising the span. There are no hydraulic components involved, the 'end lifts' lower the span onto the main bearings, and the centering pin retracts allowing the span to swing. The north span is different in that it is electro-hydraulic and has 'wedges' that need to be removed. The 'end lifts' raise the span allowing the removal of the 'wedges'. The span is then lowered onto the main bearings and the 'centering pin' retracts allowing the span to swing. 1.11 Failures of the Highway Bridge Swing Spans In 1998 there were some 127reported swing span openings. In1999, there were approximately 142openings and in2000 there were approximately 115openings. Between the years1999 and2000, there have been some 90swing span failures recorded, the majority of them on the south span. In the year2000, over 40% of the total number of attempts failed. Further, during the period 17November1998 to 21December2000, there were 27failures which resulted in the bridge remaining 'closed' to marine traffic for periods of one to eleven days. It has been reported that there are problems of compatibility between the newly-installed digital components of the process control loop and the older analog and mechanical components. Reportedly also, the automatic transfer of electric power from one source to the other is often not 'smooth' and frequently results in false information being transmitted to the PLCs and thence to the Fault Monitoring Screen. 1.12 Erroneous Status Bar Readouts during Malfunctions The Status Read on the bridge tender's computer monitor often gives an incorrect indication on the status of the south span swing process. On occasions it has been known to indicate that the bridge is open before the swing is complete, or that the centring pin is out when it is not. This leads to confusion as the object of the 'status bar' is to signal any faults in the system to the operator, allowing him to change over to the manual mode to continue the swing. 1.13 Testing of Bridge Swings Some test runs were done after the installation of the new equipment was connected with the PLCs and the computerisation of the opening and closing process of the Pitt River Road bridge. The testing was not exhaustive and did not identify all the deficiencies in the system or the effect of seasonal and climatic change. 1.14 Protocol for Bridge Openings Regulations concerning the railroad and highway bridges in the Pitt River, previously under Rules 59 and 60 of the Fraser River Harbour Commission (now the Fraser River Port Authority) By-Laws, became obsolete with the introduction of section 56 of the Canada Marine Act. A copy of the relevant section of the By-Laws, however, can still be found for the guidance of mariners, in the Sailing Directions, British Columbia Coast (SouthPortion). Accordingly, the swing spans of the bridges are opened only for vessels that cannot otherwise pass under any part of the bridges. Except for emergencies, there are stipulated times when the bridge cannot be opened. To arrange an opening, mariners have to follow the 'calling in ' protocol required by the By-Laws. Openings have to be requested 30minutes in advance of the estimated time of arrival (ETA) at the bridge and then reconfirmed not later than 10minutes prior to arrival. Communication with the bridge tender can be via VHF radio on Channel74 or by telephone. Additionally, the vessel has to signal its approach by sounding two short and two long blasts on its whistle. Both the rail and road bridges are equipped with sirens to signal an imminent opening or closing. It is further required that a vessel, having signalled for the swing span of the bridge to be opened, shall remain at a safe distance from the bridge until clearance has been given to transit. In practice, most vessels call in at60, 30and 10minutes prior to their ETA at the bridges. In addition, the master of the MillerRichmond gave advance notice two days prior to his intended passage and once again before departing his berth in Delta. 1.15 Evolution of Bridge Operating Practice The Navigable Waters Bridge Regulations (NWBR) made pursuant to the Navigable Waters Protection Act (NWPA) require that bridge spans be opened immediately, or as soon thereafter as is reasonably possible, to permit the passage of the vessel. Further, the regulations emphasize the requirement for efficient, reliable service to the marine community to be provided by organizations operating the bridges. Marine traffic users of the Pitt River Highway bridges have indicated that the span opening process is not commenced while the tug is still a safe distance away, even though repeated ETAs are given. The practice used by the bridge tenders is as follows: for upbound vessels, the highway bridge opening procedure is commenced only after the rail bridge has been opened, and for downbound vessels, the bridge opening procedure is commenced when the traffic is approximately half a mile away. 1.16 Navigation Light Signals for Marine Traffic All the bridges have a system of red and green lights to indicate the 'closed' or 'open' position of the swing spans. On the rail bridge, these are mounted on the side of the bridge facing the vessel and on the highway bridges, these are mounted at the extreme ends of the protection piers. To marine traffic, a red light indicates the swing span is closed and a green light indicates the span is open. There is no light to indicate an intermediate status of the bridge. The Navigable Waters Bridge Regulations have provisions for bridge owners to exhibit, maintain and operate lights as necessary. They do not, however, prescribe the minimum luminous intensity for bridge lights. In the Fraser River, the colour, characteristics and location of bridge lights are noted but not the range or intensity. 1.17 Operation and Maintenance of the Highway Bridge The Pitt River Highway bridge falls under the jurisdiction of the provincial Ministry of Transportation. The Ministry has in turn contracted out the operation and maintenance of the swing spans to a private company. It has however, retained the supervision and maintenance of the electrical and electronic components of the machinery. To this end the Ministry has constituted a team whose job it is to oversee the maintenance of this, and all the bridges in the Province and to ensure compliance with contractual obligations. Similarly, the private contractor has a team looking after its contractual commitments with regard to the bridges. The Ministry's team is made up of bridge engineers, electrical engineers and systems technologists. The contractor's team includes a bridge manager of operations and a manager for traffic claims. The latter is directly involved in the day-to-day operation and maintenance of the bridges. When a failure occurs during a bridge opening, according to Ministry protocol, the Electrical Department is first called out, irrespective of the actual nature of the fault which could be mechanical, electrical or electronic. The electrician then advises the bridge tender to call out technicians from the other departments, if required. 1.18 Highway Bridge Operational Statistics Statistical data since 1995 was obtained to compare failure to success ratio immediately prior to and after the upgrade. The data show that the failure to success ratio of the span swings had increased considerably post-control system upgrade. 1.19 Quality System The quality assurance system of the Ministry of Transportation and the private contractor for bridge operation and maintenance was incomplete in that: no common database was set up to record bridge repair/maintenance such as faults identified and steps taken to rectify them; there were no written operating procedures for normal or emergency opening/closing of the bridges.